The invention relates to an assembly plant for the series assembly of industrial products, especially vehicles. The assembly plant is of the type in general use at the present time in industrial manufacture, for example also in the construction of motor vehicles.
In these known assembly plants, the assembly line runs in a plurality of U-shaped loops, all of which run parallel to one another and are situated directly adjacent to one another. This conventional layout of an assembly plant offers the advantage of low expenditure on conveying technology for the return of the assembly skids from the end of the line to the beginning of the line. Because of the compact arrangement of the individual sections of the assembly line, good communication between these sections is also possible. A favorable ratio between facade length and required surface area is furthermore advantageous. Moreover, the small components, which can be delivered to the assembly line by the crate load in batches containing a large number of items, can be delivered to the assembly points via the access lanes between the sections of the assembly lines. However, logistically linking the more complex parts which are to be supplied "just in time" is difficult. Given a compact layout of this kind, the conveying systems required for this purpose are very expensive because a floor-supported conveying system for such large components is no longer possible. The only possibility is to use expensive large component overhead conveyors, which are costly to install and furthermore less flexible for subsequent changes of target location.
It is the object of the invention to optimize the generic assembly plant both logistically and in terms of operation and costs.
Taking the assembly plant of the generic type as a basis, this object is achieved, according to the invention, by an assembly plant for the series assembly of industrial products, especially vehicles, with an assembly line accommodated in a main assembly shop and with a plurality of associated assembly works for vehicle parts to be supplied. The assembly plant includes a linear--floor-supported or overhead--conveying device for slowly moving forward a series of product carriers--referred to below as "skids" for short--by means of which conveying device the main assembly line is formed. The plant also includes a plurality of pairs, each comprising two equal part-lengths of the conveying device, which are arranged parallel and adjacent to one another, i.e. in a U-shape with opposing conveying directions. Thus, the overall conveying line is divided into a plurality of mutually adjoining conveying loops. The plant further includes a plurality of separate assembly shops for relatively large and relatively complex product parts which are to be preassembled at separate locations and supplied to the assembly line "just in time". Further, a central component store for assembly components requiring little or no preassembly and taking up little space for each individual component is provided, as well as a plurality of stores for large components, arranged noncentrally in, at or next to the main assembly shop near to the assembly point. The plant feeder systems between each of the separate assembly shops and the non-central stores, on the one hand, and the assembly line, on the other, are provided for the purpose of linking the assembly shops or stores logistically to the respective workstations along the assembly line at which the relevant product part or a large component is required. U-shaped conveying loops of the assembly line are directed radially away from a center of the assembly plant and arranged so as to leave a free space between adjacent U-shaped conveying loops. At least some of the separate assembly shops and the central component store are accommodated in the free spaces between the conveying loops in immediate proximity to the main assembly shop of the assembly line.
Owing to the spread-out and preferably cross-shaped arrangement of the conveying loops of the assembly line, it is possible to accommodate in the free spaces created between the assembly lines supplier works for components to be installed. This gives short access paths from the supplier works to the main assembly line. The communication paths within the main assembly line are nevertheless very short and it is not necessary to install separate conveying devices for the return of the empty skids. Relatively complex large components can be supplied along the floor transversely to a section of the assembly line, this merely presupposing simple, floor-supported and functionally flexible conveying systems. The target location for the delivery of components of this kind can be changed as required without any great expenditure on conversion.
The advantages of the configuration of the assembly plant in accordance with the invention lie in the fact that all the following points can be provided in combination, whereas known alternative solutions only manage to provide some of the following advantageous points: 1) short communication paths within the main assembly line; 2) short feed paths for the small and standard components and medium-sized components to the various scattered assembly points from the centrally situated ends of the conveying loops or from lateral parking places for interchangeable bodies of lorries; 3) in the event of an increase in the capacity of the assembly plant, i.e. an increase in the yearly production, the assembly line can be expanded without too much trouble, without disrupting the separate assembly shops for the product components and without interrupting production on the main assembly line, by extending the free ends of the conveying loops; 4) low expenditure on conveying technology and low space requirement for the return of the empty skids or overhead conveyors from the end of the assembly line to its start; 5) short logistical links between the separate assembly shops and the respectively desired assembly point of the main assembly line; 6) short communication paths between the main assembly line, on the one hand, and the separate assembly shops, on the other; 7) flexible accommodation of the separate assembly shops between the respective conveying loops of the main assembly line, i.e. where there is an increase in the capacity of the main assembly line the separate assembly shops for the product components can also be expanded or enlarged; and 8) good ratio between site area or built-on area and the perimeter length of the assembly plant.